Now and Later by Charity Tahmaseb

From a post-apocalyptic cityscape to the year's most disastrous prom, follow eight different heroines as they navigate their way through time and space and AP World History. 

NOW 

The Trouble with Firsts: From roller-coaster rides to playing in a string quartet, Mattie's had trouble with first times. But with prom right around the corner, she'll risk asking Marcus out first. If the road to hell is paved with good intentions, then the path to prom is strewn with crepe paper streamers and petals from dying corsages. And Mattie will discover her trouble with firsts is just beginning. 

Glass Slipper: What do you do when the boy you've known forever dumps you the day before prom--with everyone in a packed cafeteria looking on? Stalk him in your pajamas, of course. For Mira, this is only the start of a not-so-Cinderella prom. 

Speechless: Jared's the boy who coaches her and kisses her, but doesn't want to be seen with her. For Kara, speech team is simply a way to beef up her extra-curriculars and spend time with the dead-sexy class clown. But now she's caught in a game that everyone wants to win--everyone except maybe Jared. 

Breaking Plans: Constance has plans, ones that include leaving her small town immediately after graduation. Prom isn't part of her agenda. Constance is proficient at breaking rules. But breaking plans? Never. Except that might be the one thing she needs to do. 

LATER 

Just a Matter of Time: 

High school junior Sadie Lin is desperate--to maintain her GPA, to score high on the SATs, for her dad to return from Afghanistan. Time seems to crawl and slip through her fingers all at once. She thinks it's all in her head. 

It's not. 

Gordon Bakersfield--Sadie's ninth grade epic crush--has plenty of time and knows where to get more. He knows someone has been stealing Sadie's time. And while he's not sure how to make it stop, he's hoping to try. But can Sadie trust him? 

Only time will tell. 

The Maze: Cadet Eppie Langtry navigates the cold and endless maze as part of the Academy's final training exercise. Her exploration leads her to a fellow cadet, and their combined curiosity triggers something no one expects--least of all the cadre running the maze. 

What Little Remains: In a post-apocalyptic city, Kit ekes out an existence by tending to her rooftop garden. A rift in time brings her a new friend from the past--and something else far more menacing. 

Inside Out: When Lexia befriends a girl from outside a luxury spa facility, she starts seeing the cracks in her mother's disastrous fifth marriage, the world in which she lives, and her own future.